中文摘要：

根据二氧化硫（SO2）气体在紫外光照射下激发出一定波长荧光的机理,结合光纤传感技术,研制出一种大气SO2浓度检测系统。整个系统由光学系统和电路系统两部分组成。光学系统采用了以脉冲氙灯作为激发光源的双光路检测方法,克服了光源不稳定带来的误差,使测量结果具有更高的精度。电路系统应用了微弱信号检测技术,使淹没在噪声信号中的微弱荧光信号得到有效的提取和放大。通过性能实验表明,在浓度范围为（0～1500）×10^-9的SO2,该系统有良好的线性和稳定性,且具有较高的测量精度和较强的抗干扰能力。

英文摘要：

Based on the mechanism that the sulfur dioxide can be stimulated to emit some wavelength fluorescence in the ultraviolet light,and combined with the optical-fiber sensing technology,a new system which can be applied to detect the concentration of sulfur dioxide（SO2） in air is developed.The whole system consists of an optical system and a circuit system.The optical system adopts the double-optical paths detection method using the xenon flash lamp as the excitation light source and overcomes the error from instability of excitation light source,thus higher precision of measurement has been achieved.The circuit system adopts the technique of weak signal measuring,which can make the weak fluorescence signal of intermixing noise signal extract and magnify effectively.The exeperiment shows that this system can maintain a good linearity and stable detection when sulfur dioxide concentration range is between 0 and 1 500×10^-9,and has high measuring accuracy and strong antijamming ability.